Undetectable equals untransmittable (U = U): awareness and associations with health outcomes among people living with HIV in 25 countries.

<bold>Objectives: </bold>'Undetectable equals Untransmittable' (U=U) is an empowering message that may enable people living with HIV (PLHIV) to reach and maintain undetectability. We estimated the percentage of PLHIV who ever discussed U=U with their main HIV care provider, and measured associations with health-related outcomes. Secondarily, we evaluated whether the impact of the U=U message varied between those who heard it from their healthcare provider (HCP) vs from elsewhere.<bold>Methods: </bold>Data were from the 25-country 2019 Positive Perspectives Survey of PLHIV on treatment (n=2389). PLHIV were classified as having discussed U=U with their HCP if they indicated that their HCP had ever told them about U=U. Those who had not discussed U=U with their HCP but were nonetheless aware that 'My HIV medication prevents me from passing on HIV to others' were classified as being made aware of U=U from non-HCP sources. Multivariable logistic regression was used to measure associations between exposure to U=U messages and health outcomes.<bold>Results: </bold>Overall, 66.5% reported ever discussing U=U with their HCP, from 38.0% (South Korea) to 87.3% (Switzerland). Prevalence was lowest among heterosexual men (57.6%) and PLHIV in Asia (51.3%). Compared with those unaware of U=U, those reporting U=U discussions with their HCP had lower odds of suboptimal adherence (AOR=0.59, 95% CI 0.44 to 0.78) and higher odds of self-reported viral suppression (AOR=2.34, 95% CI 1.72 to 3.20), optimal sexual health (AOR=1.48, 95% CI 1.14 to 1.92) and reporting they 'always shared' their HIV status (AOR=2.99, 95% CI 1.42 to 6.28). While exposure to U=U information from non-HCP sources was beneficial too, the observed associations were attenuated relative to those seen with reported discussions with HCPs.<bold>Conclusion: </bold>HCP discussion of U=U with PLHIV was associated with favourable health outcomes. However, missed opportunities exist since a third of PLHIV reported not having any U=U discussion with their HCP. U=U discussions with PLHIV should be considered as a standard of care in clinical guidelines. [ABSTRACT FROM AUTHOR]